A walking model to assess the onset of analgesia in osteoarthritis knee pain

Effects of Analgesics on Self-Reported Physical Function and Walking Ability in People With Hip or Knee Osteoarthritis: A Systematic Review and Meta-Analysis

OBJECTIVE

Hip and knee osteoarthritis are among the leading causes of global disability, and one of the main aims of the management is to improve physical function. The objective of this review was to investigate the effect of analgesics on physical function (self-reported physical function and walking ability).

METHODS

A systematic review and meta-analysis of the findings were performed. Randomized controlled trials investigating the effect of analgesics on self-reported physical function and walking ability were included. Analgesics were orally administered acetaminophen, nonsteroidal antiinflammatory drugs (NSAIDs), or opioids. Data were pooled in a random-effects model, and the standardized mean difference (SMD) with 95% CI was calculated (SMDs: 0.2-0.4 = small, 0.5-0.7 = medium, and ≥0.8 = large effect sizes). The quality of the evidence was evaluated according to the Grading of Recommendations Assessment, Development, and Evaluation approach.

RESULTS

A total of 1454 studies were identified, of which 33 were included. On self-reported physical function, the results showed low- to moderate-quality evidence for a small beneficial effect of acetaminophen (SMD = -0.13 [95% CI = -0.26 to 0.00]), NSAIDs (SMD = -0.32 [95% CI = -0.37 to -0.27]), or opioids (SMD = -0.20 [95% CI = -0.32 to -0.09]). There was moderate-quality evidence for a small effect of NSAIDs on pain during walking (SMD = -0.34 [95% CI = -0.45 to -0.23]).

CONCLUSION

In people with hip or knee osteoarthritis, there was low- to moderate-quality evidence for small beneficial effects of analgesics on physical function and walking ability.

IMPACT

Analgesics may improve physical function by reducing pain during exercise and walking.

Ambulatory support moment contribution patterns and MRI-detected tibiofemoral and patellofemoral disease worsening in adults with knee osteoarthritis: A preliminary study

We investigated whether baseline sagittal-plane ankle, knee, and hip contribution to the total support moment (TSM) are each associated with baseline-to-2-year tibiofemoral and patellofemoral tissue damage worsening in adults with knee osteoarthritis. Ambulatory lower-limb kinetics were captured and computed. TSM is the sum of ankle, knee, and hip extensor moments at each instant during gait. Ankle, knee, and hip contributions to TSM were computed as joint moments divided by TSM, expressed as percentages. Participants underwent MRI of both knees at baseline and 2 years later. Logistic regression models assessed associations of baseline ankle contribution to TSM with baseline-to-2-year cartilage damage and bone marrow lesion worsening, adjusted for age, sex, BMI, gait speed, disease severity, and pain. We used similar analytic approaches for knee and hip contributions to TSM. Sample included 391 knees from 204 persons (age[SD]: 64[10] years; 76.5% women). Greater ankle contribution may be associated with increased odds of tibiofemoral cartilage damage worsening (OR = 2.38; 95% CI: 1.02-5.57) and decreased odds of patellofemoral bone marrow lesion worsening (OR = 0.14; 95% CI: 0.03-0.73). The ORs for greater knee contribution were in the protective range for tibiofemoral compartment and in the deleterious range for patellofemoral. Greater hip contribution may be associated with increased odds of tibiofemoral worsening (OR = 2.71; 95% CI: 1.17-6.30). Greater ankle contribution to TSM may be associated with baseline-to-2-year tibiofemoral worsening, but patellofemoral tissue preservation. Conversely, greater knee contribution may be associated with patellofemoral worsening, but tibiofemoral preservation. Preliminary findings illustrate potential challenges in developing biomechanical interventions beneficial to both tibiofemoral and patellofemoral compartments.

Tensile strain and altered synovial tissue metabolism in human knee osteoarthritis

Synovium is critical for maintaining joint homeostasis and may contribute to mechanobiological responses during joint movement. We investigated mechanobiological responses of whole synovium from patients with late-stage knee osteoarthritis (OA). Synovium samples were collected during total knee arthroplasty and assigned to histopathology or cyclic 10% tensile strain loading, including (1) static (control); (2) low-frequency (0.3 Hz); and iii) high-frequency (1.0 Hz) for 30-min. After 6-h incubation, tissues were bisected for RNA isolation and immunostaining (3-nitrotyrosine; 3-NT). RNA sequencing was analyzed for differentially expressed genes and pathway enrichment. Cytokines and lactate were measured in conditioned media. Compared to controls, low-frequency strain induced enrichment of pathways related to interferon response, Fc-receptor signaling, and cell metabolism. High-frequency strain induced enrichment of pathways related to NOD-like receptor signaling, high metabolic demand, and redox signaling/stress. Metabolic and redox cell stress was confirmed by increased release of lactate into conditioned media and increased 3-NT formation in the synovial lining. Late-stage OA synovial tissue responses to tensile strain include frequency-dependent increases in inflammatory signaling, metabolism, and redox biology. Based on these findings, we speculate that some synovial mechanobiological responses to strain may be beneficial, but OA likely disturbs synovial homeostasis leading to aberrant responses to mechanical stimuli, which requires further validation.

Similar Effects of Exercise Therapy, Nonsteroidal Anti-inflammatory Drugs, and Opioids for Knee Osteoarthritis Pain: A Systematic Review with Network Meta-analysis

OBJECTIVE

To compare the effectiveness of opioids, nonsteroidal anti-inflammatory drugs (NSAIDs), and exercise therapy for knee osteoarthritis pain.

DESIGN

Systematic review with network meta-analysis.

LITERATURE SEARCH

We searched the databases MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials from inception to April 15, 2021. Web of Science was used for citation tracking.

STUDY SELECTION CRITERIA

Randomized controlled trials comparing exercise therapy, NSAIDs, and opioids in any combination for knee osteoarthritis pain.

DATA SYNTHESIS

Network meta-analysis comparing exercise therapy, NSAIDs, opioids, and placebo/control for knee osteoarthritis pain. Additional trials from previous reviews were included to create the external placebo/control anchor.

RESULTS

We included 13 trials (1398 patients) with direct comparisons, supplemented with data from 101 additional trials. The treatment effect of NSAIDs for knee osteoarthritis pain was similar to that of opioids (standardized mean difference [SMD], 0.02; 95% confidence interval [CI], -0.14 to 0.18; Grading of Recommendations, Assessment, Development and Evaluations [GRADE]: low certainty). Exercise therapy had a larger effect than NSAIDs (SMD, 0.54; 95% CI, 0.19 to 0.89; GRADE: very low certainty). No estimate could be made for exercise vs opioids due to the lack of studies. Exercise therapy ranked as the "best" intervention in the network meta-analysis, followed by NSAIDs, opioids, and placebo/control intervention (GRADE: low certainty).

CONCLUSION

Exercise therapy ranked as the best treatment for knee osteoarthritis pain, followed by NSAIDs and opioids. The difference between treatments was small and likely not clinically relevant, and the overall confidence in the ranking was low. The results highlight the limited evidence for comparative effectiveness between exercise therapy, NSAIDs, and opioids for knee osteoarthritis pain. J Orthop Sports Phys Ther 2022;52(4):207-216. doi:10.2519/jospt.2022.10490.

Study Protocol Modeling Evoked Pain in Older African Americans With Knee Osteoarthritis

BACKGROUND

African American (AA) older adults with knee osteoarthritis experience more severe chronic pain and advanced physical disability. One of the most prominent stimuli that provokes knee pain is movement. Research suggests that, compared to Whites, AAs report significantly higher movement-evoked pain (MEP) in the knee. However, little is known about the biopsychosocial-behavioral mechanisms underlying MEP.

OBJECTIVES

The aim of the study was to present a study protocol to (a) characterize the biopsychosocial-behavioral mechanisms that predict MEP in AAs with knee osteoarthritis and (b) develop a targeted, mechanism-based self-management intervention to reduce MEP and maximize movement.

METHODS

An observational, mixed-methods cohort study will enroll 90 AA/Black adults (ages 55-90 years) to understand intraindividual and interindividual effects on MEP. Participants will complete assessments of MEP, function and gait, biopsychosocial-behavioral questionnaires, quantitative sensory testing, and 7-day ecological momentary assessments of pain and related symptoms. For the qualitative phase, focus groups will be conducted to co-construct a mechanism-based pain self-management intervention.

RESULTS

We will develop phenotypes of MEP based on biopsychosocial-behavioral predictors and correlate measures of MEP with function. Our central hypothesis is that higher levels of MEP will predict lower self-reported function and poorer performance on functional tasks and that multiple biopsychosocial and behavioral factors will be associated with MEP and function. Predictors may serve as risk or protective factors for MEP and physical function. In targeting the biopsychosocial-behavioral mechanisms of MEP, we anticipate that older AAs may request that intervention components include culturally tailored self-management education, movement/physical activity training, treatment decision-making skills, coaching, spirituality, and social/kinship support.

CONCLUSION

Osteoarthritis is now the single most common cause of disability, mobility limitations, and persistent pain in older adults-especially AA older adults. To our knowledge, this will be the first study to systematically phenotype MEP in an older racial minority population with knee osteoarthritis and will be relevant for reducing knee pain and improving function.

Staircase-evoked Pain May be More Sensitive Than Traditional Pain Assessments in Discriminating Analgesic Effects: A Randomized, Placebo-controlled Trial of Naproxen in Patients With Osteoarthritis of the Knee

OBJECTIVES

Analgesic trials often fail to show a significant effect even when medications with known efficacy are tested. This could be attributed to insufficient assay sensitivity of analgesic trials, which may be due, in part, to the insensitivity of pain-related outcome measures. The aim of this methodological study was to assess the responsiveness of evoked pain generated by the staircase procedure compared with other commonly used pain outcomes in knee osteoarthritis.

METHODS

This was a randomized, double-blind, placebo-controlled, cross-over trial of 1-week treatment of naproxen versus placebo. Participants were assigned to one of the 2 treatment sequences (naproxen-placebo or placebo-naproxen). Pain-at-rest, evoked pain using the Staircase-Evoked Pain Procedure (StEPP), pain diary, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) data were collected before and at the end of each treatment sequence.

RESULTS

A total of 55 osteoarthritis patients (30 M, 25 F) completed the study. Among all pain assessments, evoked pain was the most sensitive outcome to detect treatment effects, with Standardized Effect Size (SES) of 0.47 followed by the WOMAC and pain-at-rest with SES of 0.43 and 0.36, respectively. Sample size calculations demonstrated that compared with spontaneous pain, the evoked pain model reduces required number of subjects by 40%.

DISCUSSION

Study results support our hypothesis that evoked pain using the StEPP may demonstrate greater responsiveness to treatment effects compared with traditional pain-related outcome measures. Accordingly, these results may facilitate development and validation of other chronic pain-related evoked pain models, which could contribute to future research and development of new analgesics.

Tramadol for osteoarthritis

BACKGROUND

Tramadol is often prescribed to treat pain and is associated physical disability in osteoarthritis (OA). Due to the pharmacologic mechanism of tramadol, it may lead to fewer associated adverse effects (i.e. gastrointestinal bleeding or renal problems) compared to non-steroidal anti-inflammatory drugs (NSAIDs). This is an update of a Cochrane Review originally published in 2006.

OBJECTIVES

To determine the benefits and harms of oral tramadol or tramadol combined with acetaminophen or NSAIDs in people with osteoarthritis.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and Embase databases, as well as the US National Institutes of Health and World Health Organization trial registries up to February 2018. We searched the LILACS database up to August 2015.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that evaluated the effect of tramadol, or tramadol in combination with acetaminophen (paracetamol) or NSAIDs versus placebo or any comparator in people with osteoarthritis.

DATA COLLECTION AND ANALYSIS

We used standard methodologic procedures expected by Cochrane.

MAIN RESULTS

We included 22 RCTs (11 more than the previous review) of which 21 RCTs were included in meta-analyses for 3871 participants randomized to tramadol alone or tramadol in combination with another analgesic and 2625 participants randomized to placebo or active control. Seventeen studies evaluated tramadol alone and five evaluated tramadol plus acetaminophen. Thirteen studies used placebo controls and eleven studies used active controls (two trials had both placebo and active arms). The dose of tramadol ranged from 37.5 mg to 400 mg daily; all doses were pooled. Most trials were multicenter with a mean duration of two months. Participants were predominantly women with hip or knee osteoarthritis, with a mean age of 63 years and moderate to severe pain. There was a high risk of selection bias as only four trials reported both adequate sequence generation and allocation concealment. There was a low risk for performance bias as most studies blinded participants. There was a high risk of attrition bias as 10/22 trials showed incomplete outcome data. Most of the trials were funded by the pharmaceutical industry.Moderate quality evidence (downgraded due to risk of bias) indicated that tramadol alone and in combination with acetaminophen had no important benefit on pain reduction compared to placebo control (tramadol alone: 4% absolute improvement, 95% confidence interval (CI) 3% to 5%; 8 studies, 3972 participants; tramadol in combination with acetaminophen: 4% absolute improvement, 95% CI 2% to 6%; 2 studies, 614 participants).Fifteen out of 100 people in the tramadol group improved by 20% (which corresponded to a clinically important difference in pain) compared to 10/100 in the placebo group (5% absolute improvement). Twelve out of 100 people improved by 20% in the tramadol in combination with acetaminophen group compared to 7/100 in the placebo group (5% absolute improvement).Moderate quality evidence (downgraded due to risk of bias) indicated that tramadol alone and in combination with acetaminophen led to no important benefit in physical function compared to placebo (tramadol alone: 4% absolute improvement, 95% CI 2% to 6%; 5 studies, 2550 participants; tramadol in combination with acetaminophen: 4% absolute improvement, 95% CI 2% to 7%; 2 studies, 614 participants).Twenty-one out of 100 people in the tramadol group improved by 20% (which corresponded to a clinically important difference in physical function) compared to 16/100 in the placebo group (5% absolute improvement). Fifteen out of 100 people improved by 20% in the tramadol in combination with acetaminophen group compared to 10/100 in the placebo group (5% absolute improvement).Moderate quality evidence (downgraded due to risk of bias) indicated that, compared to placebo, there was a greater risk of developing adverse events with tramadol alone (risk ratio (RR) 1.34, 95% CI 1.24 to 1.46; 4 studies, 2039 participants) and tramadol in combination with acetaminophen compared to placebo (RR 1.91, 95% CI 1.32 to 2.76; 1 study, 308 participants). This corresponded to a 17% increase (95% CI 12% to 23%) with tramadol alone and 22% increase (95% CI 8% to 41%) with tramadol in combination with acetaminophen.The three most frequent adverse events were nausea, dizziness and tiredness. Moderate quality evidence (downgraded due to risk of bias) indicated that there was a greater risk of withdrawing from the study because of adverse events with tramadol alone compared to placebo (RR 2.64, 95% CI 2.17 to 3.20; 9 studies, 4533 participants), which corresponded to a 12% increase (95% CI 9% to 16%).Low quality evidence (downgraded due to risk of bias and inconsistency) indicated that there was a greater risk of withdrawing from the study because of adverse events with tramadol in combination with acetaminophen compared to placebo (RR 2.78, 95% CI 1.50 to 5.16; 2 studies, 614 participants), which corresponded to a 8% absolute improvement (95% CI 2% to 19%).Low quality evidence (downgraded due to risk of bias and imprecision) indicated that there was a greater risk of developing serious adverse events with tramadol alone compared to placebo (110/2459 participants with tramadol compared to 22/1153 participants with placebo; RR 1.78, 95% CI 1.11 to 2.84; 7 studies, 3612 participants), which corresponded to a 1% increase (95% CI 0% to 4%). There were no serious adverse events reported in one small study (15 participants) of tramadol with acetaminophen compared to placebo.

AUTHORS' CONCLUSIONS

Moderate quality evidence indicates that compared to placebo, tramadol alone or in combination with acetaminophen probably has no important benefit on mean pain or function in people with osteoarthritis, although slightly more people in the tramadol group report an important improvement (defined as 20% or more). Moderate quality evidence shows that adverse events probably cause substantially more participants to stop taking tramadol. The increase in serious adverse events with tramadol is less certain, due to the small number of events.

Gait mechanics contribute to exercise induced pain flares in knee osteoarthritis

Background

Exercise-induced pain flares represent a significant barrier for individuals with knee osteoarthritis to meet physical activity recommendations. There is a need to understand factors that contribute to pain flares and the potential for the motor system to adapt and reduce joint loading should a flare occur. The study aim was to examine the impact of a bout of exercise on self-reported pain, walking mechanics and muscle co-contraction for participants with knee osteoarthritis.

Methods

Thirty-six adults (17 healthy older and 19 knee osteoarthritis) participated in this study. Self-reported pain, joint mechanics and muscle co-activation during gait at two self-selected speeds were collected before and after a 20-min preferred pace treadmill walk (20MTW).

Results

Eight of nineteen osteoarthritis participants had a clinically significant pain flare response to the 20MTW. At baseline the participants that did not experience a pain flare had smaller knee flexion and total reaction moments compared to both the participants with pain flares (p = 0.02; p = 0.05) and controls (p < 0.001; p < 0.001). In addition, the 2nd peak knee adduction (p = 0.01) and internal rotation (p = 0.001) moments were smaller in the no flares as compared to controls. The pain flare participants differed from controls with smaller knee internal rotation moments (p = 0.03), but greater relative hamstrings (vs. quadriceps) and medial (vs. lateral) muscle activation (p = 0.04, p = 0.04) compared to both controls and no flare participants (p = 0.04, p = 0.007). Following the 20MTW there were greater decreases in the 1st and 2nd peak knee adduction (p = 0.03; p = 0.02), and internal rotation (p = 0.002) moments for the pain flare as compared to the no flare group. In addition, for the pain flare as compared to controls, greater decreases in the knee flexion (p = 0.03) and internal rotation (p = 0.005) moments were found.

Conclusions

Individuals who adapt their gait to reduce knee joint loads may be less susceptible to exercise-induced pain flares. This highlights a potential role of gait biomechanics in short-term osteoarthritis pain fluctuations. The results also suggest that despite the chronic nature of osteoarthritis pain, the motor system’s ability to respond to nociceptive stimuli remains intact.

Electronic supplementary material

The online version of this article (10.1186/s12891-019-2493-4) contains supplementary material, which is available to authorized users.

[Consensus statement on the use of acetaminophen/tramadol in patients with moderate-severe pain]

OBJECTIVES

To present recommendations on the use of the paracetamol/tramadol (P/T) combination in patients with moderate-intense pain based on best evidence and experience.

METHODS

The method of nominal groups and Delphi was followed, and supported by a systematic literature review (SLR). A multidisciplinary panel of 12 experts in pain management was selected. In the first nominal group meeting, the aim, scope, users, and sections of the consensus document, were defined, along with the preliminary general recommendations. For the SLR, the inclusion and exclusion criteria, as well as the search strategies, were defined. Two reviewers selected and analysed the articles. This evidence was discussed in a second nominal group meeting, and definitive recommendations were developed. For each recommendation, the evidence levels and grade of recommendation grades were classified according to the Oxford model, and the grade according to the Delphi technique. It was defined as an agreement if at least 70% of the participants scored ≥7 for each recommendation (1=total disagreement to 10=total agreement).

RESULTS

A total of 20 recommendations were produced, which covered general aspects, such as the assessment of pain, and those specific to P/T management. These latter included the indications of the P/T combination (patient profile, dosing, prescription, formulations), risk management (contraindications, precautions, interactions, concomitant use with other medications, follow-up, special situations), and patient education.

CONCLUSIONS

These recommendations attempt to resolve any of the routine clinical questions, and help in the making of decisions on the use of the P/T combination in patients with moderate-intense pain.